Advice Needed Dreambox 8000 disconnecting from network when transferring recordings

Yes, it's a long shot. You might need to reconfigure ip addresses too, or type "arp -a" in a cmd window to see if it's been auto configured.
If you decide to remove the hd you could install a device driver from www.ext2fsd.com to make windows read ext2 partitions. (I haven't tried it myself, I've used fs-driver.org in the past but that one seems abandoned.)

Have you tried changing the IP address of your dreambox?
It may by clashing or to close to IP address used on the same network.
Just an idea!